Related resources for this article

Introduction

What Is Heat?

Measuring Temperature

Measuring Heat

How Heat Is Transferred

Thermodynamics

The Laws of Thermodynamics

The First Law

The Second Law

Most kinds of energy can be changed entirely into work or other forms of energy and back again. However, heat is fundamentally different. Not all of the heat generated in a system can be changed back into work or another form of energy, not even in principle. This fundamental limitation is expressed by the second law of thermodynamics.

In a car engine, for example, hot gas expands and causes pistons to move. The mechanical energy…

The Third Law

Discovering the Nature of Heat

Additional Reading

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